The Effect of Gut Hormone on the Digestive Enzyme Secretion in Chickens

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1) Effect of amino acid administration on the pancreatic secretion of digestive enzyme, amylase, trypsinogen and chymotrypsinogen was studied after wing vein injection of an amino acid mixture or combination of selected amino acids in the presence of Cholecystokinin (CCK). It is suggested that threonine (Thr) and phenylalanine (Phe) may have a specific regulatory role in the secretion of pancreatic enzymes in chicks when administered simultaneously. 2) Effect of Phe on the pancreatic amylase secretion in chicks was investigated. Phe did not have stimulatory effect on pancreatic amylase secretion in the absence or presence of CCK. Effect of Tyrosine (Tyr) on amylase secretion was similar to that of Phe. Birds were injected intraperitoneally with p-Chlorophenylalanine (p-CP), which is an inhibitor of Phe hydroxylase, or saline 1 day before the collection of pancreatic amylase. Both the chicks showed increased amylase secretion with CCK, whereas the response was at a drastically reduced r … More ate in chicks with the p-CP. 3) Whether ingestion of soya-bean trypsin inhibitor (SBTI) alters the release of CCK was investigated in chickens. It was concluded that SBTI by itself enhanced CCK release into circulation in a dose-dependent fashion. 4) Whether the ingestion of excess Phe or Tyr in diets alters the release of CCK was investigated in chickens. Plasma CCK levels were enhanced by both Phe and Tyr excess diets, but the crop emptying rate was delayed in chicks administered Phe excess diet. 5) To investigate the actions of Acetylcholine (Ach) and Caerulein (Cae) on acinar cells of the excrine pancreas of chicks, amylase release was measured in vitro. The application of Ach or Cae caused a dose dependent increase in amylase release from the superfused segment of pancreas. Birds were injected intraperitoneally with p-CP or saline 1 day before the experiment. The weight and cell size of pancreas increased by the p-CP treatment. The response of amylase secretion to treated with Ach significantly decreased in the pancreatic segment treated with p-CP, compared with the control. Less